Fig. 8.

Robust gaze shifts despite variable directions and goals for platforms (default parameter set in all cases). A and B: 70° gaze shifts with variable initial platform orientations below the gaze goal; this can result in early reversals of the eye so that it may move opposite to the head well before fixation (consistent with report by Boulanger et al. 2012). Gaze shifts are quite robust, particularly for cross-midline shifts. In C, the gaze goal is between the initial orientations of the eye and head, requiring a 20° gaze shift; now the eye and gaze both move opposite to the head throughout saccade and fixation intervals, delimited by the switching line (matches Fig. 10 in Goossens and Van Opstal 1997). D: independent head targets, determined using the head offset input in Fig. 3, are presented concurrently with the 40° target. The modified head trajectories for head goals of 35° (dashed lines) or 15° (dotted lines) barely affect the 40° gaze shift so long as the eye remains in its working range during the eye/head interactions. The default head trajectory (solid line) settles between the two cases at 25° when head offset is null. Model parameters are fixed (except for non-zero head goals in D).